1. Field of Use
This invention relates generally to chain drives including sprockets and flexible chains employed therewith and, in particular, to the configuration and arrangement of the sprocket teeth.
2. Description of the Prior Art
Some chain drives, such as are used in agricultural machinery or the like, employ a drive sprocket and a driven sprocket, both rotatable in a common plane about their respective axes, and connected by an endless flexible single strand roller chain wherein both chain flights move in the said common plane transverse to the sprocket axes. Such chains sometimes comprise alternately arranged articulatable roller links and pin links, with each link comprising a pair of laterally spaced apart link members or plates defining a tooth-engaging link opening therebetween. Typically, the spacing between the pin link plates in each pin link (measured in a direction transverse to the aforesaid common plane) is greater than that between the roller link plates in each roller link thereby resulting in alternate wide and narrow links and link openings. In such an arrangement, using a conventional tapered tooth sprocket wherein sprocket teeth are all of the same width (measured in a direction transverse to the aforesaid common plane), if the oncoming chain flight is deflected or displaced from the aforesaid common plane for some reason, there is usually some initial misalignment and interference between each advancing sprocket tooth and the oncoming chain link with which it must engage. More specifically, many such chains, especially those equipped with attachment links as in agricultural machinery whereby conveyor mechanisms are attached to the chains, may have loads applied to them in a direction perpendicular to the aforesaid common plane in which the chain lies and moves. Unless the chain is kept quite taut, a displacement of the chain out of the plane of the sprocket will occur. Depending upon the looseness of the chain and the difference between the sprocket tooth width and the distance (width) between the roller link plates, the chain can often deflect enough to cause the tip of a tooth entering a chain link opening to meet the edge of a roller link plate, no matter how thin the link edge might be, rather than feeding into the space or opening between the link plates. This action then causes the chain to attempt to ride along the outside diameter of the sprocket. Generally, this cannot occur and, if loose, the chain will climb completely off of the sprocket or, if taut, be broken in two.